PROJECT SUMMARY The number of infants born to mothers with opioid use disorders (OUDs) has more than tripled in the past 15 years and the first year postpartum is an extremely high-risk time for maternal overdose and death. A federal system of child development programs, called Early Intervention, provides in-home support services to many families affected by OUDs in the first year of a newborn's life. However, targeted interventions for parents with OUDs are not a standard element of the services provided. Mothering from the Inside Out is an evidence- based intervention for parents with substance use disorders proven to decrease the rate of relapse and improve parent-child interactions. This intervention is currently delivered through addiction treatment centers by bachelor- and master- level counselors to parents of children over 11 months of age. Yet, clinic-based mental health services are notoriously difficult for postpartum women to access, adding to the heightened risk women in recovery face following the birth of a child. I propose harnessing the infrastructure and existing therapeutic relationships developed by Early Intervention programs to make the evidence-based intervention, Mothering from the Inside Out, more readily accessible to postpartum women with OUDs. With the support of a KL2 award, I have taken a community-engaged approach to develop detailed intervention adaptation and integration strategies for this new setting, called Promoting Caregiver-child Attachment and Recovery through Early Intervention (pCARE). We are currently in the process of beta-testing the training and deployment of pCARE with six Early Intervention providers and 10 mothers in recovery from OUDs. This K23 application details a strategic approach to further refine and test the acceptability and feasibility of pCARE. My research plan will utilize iterative feedback from a wide group of key stakeholders following the beta-test to refine the pCARE intervention (Aim 1). We will then assess the feasibility, acceptability, and fidelity of pCARE (Aim 2), and explore changes in parental functioning (Aim 3) in a pilot feasibility trial with 40 mothers randomized to receive either pCARE or standard Early Intervention services. My work is guided by the expertise of my outstanding mentorship team and community partners. With the support of by my mentors, I can achieve my educational goal to become a behavioral intervention researcher through the following objectives: gain content expertise in addiction medicine with a focus on pregnant and postpartum women; develop foundational knowledge of behavioral intervention theory and research; and obtain advanced training in clinical trial design and statistical methods relevant to prospective clinical trials. At the end of this award, I will have a complete package including a refined intervention, optimized study procedures, and an understanding of how to further improve the acceptability and feasibility of pCARE for further testing. I will be positioned to test the intervention in a fully powered effectiveness trial and begin closing the research-to-practice gap that exists for this vulnerable population.